OBJECTIVES: a. Detailed studies of the molecular array of inorganic ions in the initial deposits of Ca-P in bone and cartilage by analytical chemical analyses, X-ray diffraction (radial distribution function) and 31P-NMR on the mineral phase in the solid state and the changes it undergoes with maturation. b. Correlation of these data in (a) above with transmission electron microscopy, electron diffraction, and high resolution electron probe microanalysis using thin sections and fractions separated by density centrifugation. c. Isolation of the non-collagenous phosphopeptides of bone, cartilage and calcified tendon and their chemical and physical characterization, including 31P-NMR, Ca2 ions-binding properties and comparison of the phosphoproteins of dentin, bone and calcified cartilage in the same species. d. Location of the gamma-glutamyl phosphate in alpha 2 chains of bone collagen. e. Further studies on the biosynthesis of the gamma-carboxyglutamic acid-containing peptides of bone matrix, its primary structure (amino acid sequence) and its possible role in bone tissue metabolism. f. Biosynthesis and nature of collagen synthesized during repair of cartilage and during the development of degenerative osteoarthritis in experimental animals. g. Correlation of the chemical composition, physical chemical interaction properties, and the wear of normal articular cartilage in vitro and during development of experimental osteoarthritis. h. Further characterization of mouse and chick bone collagenase, both active and latent, and their immunocytochemical localization.